New species of Eupalaestrus from Argentina ( Araneae , Theraphosidae , Theraphosinae )

A new species of Eupalaestrus Pocock, 1901 from northern Argentina is described and illustrated. Males and females of Eupalaestrus larae sp. nov. differ from those all other species of the genus by the color with distinct two parallel longitudinal stripes on the femora, patellae, tibiae and one longitudinal stripe reaching half of metatarsi; the presence of a thickened femur and tibia IV; a straight embolus of the male palpal bulb and retrolateral keel pronounced. Specimens were captured in Chaco province, inhabiting unflooded flat grasslands open areas inside forest in transitional Chaco eco-region.

Theraphosidae is a family of spiders with 932 described species (Platnick, 2012), comprising more than one third of the mygalomorph species (coddington & levi, 1991).It is distributed throughout all tropical and many subtropical areas in all continents and includes many of the largest spider species.Very little is known on the biology of the Theraphosidae, and its taxonomy is in a chaotic state (Raven, 1990).
In a recent survey carried out in Presidencia Roque Sáenz Peña, Chaco province, Argentina, a new species of Eupalaestrus was discovered and is herein described.

MATERIAL AND METHODS
The following abbreviations are utilized: A, male palpal bulb apical keel; ALE, anterior lateral eyes; AME, anterior median eyes; d, dorsal; OQ, ocular quadrangle (including lateral eyes); p, prolateral; PI, male palpal bulb prolateral inferior keel; PLE, posterior lateral eyes; PME, posterior median eyes; PS, male palpal bulb prolateral superior keel; r, retrolateral; R, male palpal bulb retrolateral keel; SA, male palpal bulb subapical keel; v, ventral.The material studied are deposited in the arachnological collection of the Museo de La Plata (MLP, Luis Pereira), Buenos Aires, Argentina.Spine notation follows PetRunkevitch (1925).Palpal bulb structure classification follows BeRtani (2000).Urticating hairs classification follows cooke et al. (1972).We made measurements using a stereomicroscope equipped with a calibrated ocular micrometer scale and a digital caliper with an error of 0.01 millimeters rounded up to one significant decimal where appropriate.Images of the specimens were obtained under a stereomicroscope with a mounted digital camera.All measurements are in millimeters.
Etymology.This species is named in honor of J. Barneche's daughter, Lara.
Diagnosis.Males and females of Eupalaestrus larae sp.nov.differ from those all other species of the genus by the color with distinct two parallel longitudinal stripes on the femora, patellae, tibiae and one longitudinal stripe reaching half of metatarsi (Figs 1, 5).Eupalaestrus larae sp.nov.differs from E. weijenberghi by the thickened femur III; from E. spinosissimus by the absence of stiff setae on tibia and metatarsus IV and from E. guyanus by the less circular main body of the male palpal bulb (illustrated by gaBRiel, 2009).Eupalaestrus larae sp.nov.resembles E. campestratus by the color pattern and the thickened tibia IV but differs from this species by the presence of a thickened femur and tibia IV (Fig. 7) and by the straighter embolus of the male palpal bulb and retrolateral keel pronounced (Figs 3, 4) (illustrated by BeRtani, 2001).
Distribution.Known from central and western Chaco province, near Santiago del Estero province, Argentina.
Natural history.Spiders were observed in the field exhibiting a noticeable aggregation, with many specimens in a few square meters.At night, they usually stay outside the burrow waiting for a prey and can be easily found.Eupalaestrus larae sp.nov.inhabit the eco-region of transitional Chaco, between humid and dry Chaco.Specimens were found in unflooded flat grasslands open areas inside forest habitat (Fig. 8).Moreover, this species is abundant in modified and disturbed habitats such as golf fields (Jorge Barneche, pers.obs.).Burrows (Fig. 9) are deep and can easily exceed the 50 centimeters; the entrances can vary from 32.92 mm to 36.81 mm according to the spider size and sex and temperatures inside burrows can range from 30 to 33°C while the outside temperature in their typical habitat can reach values of 37 to 39°C in summer.Eupalaestrus larae sp.nov. is a sympatric species with the theraphosid Acanthoscurria chacoana Brèthes 1909, and both species can be found in the same habitat, but A. chacoana inhabit inside the forest and construct their burrows under logs or in base of trunks.An analogous situation occurs in Uruguay and Brazil, where two sympatric theraphosid species of the genus Eupalaestrus and Acanthoscurria occupy the same habitat in grasslands (PéRez-mileS et al., 2005) and in Pantanal Matogrossensse (Rogerio Bertani, pers.comm.).
Eupalaestrus larae sp.nov., length of leg and palpal segments of male.